1994 GMC Suburban Removal of Drive Shaft

Driveway Mechanic: I am trying to replace Front & Rear Universal Joints. I have removed the 4 rear 11mm bolts but the drive shaft will not drop. Do I need to remove the four LARGE bolts from the trans housing? If so, will tranny fluid leak out? Any hints on U-joint removal once the drive shaft is dropped?
GMC Sub1500/350V8/4WD. PLEASE ADVISE ASAP.
Vehicle is up on ramps/blocks. Regards, Joe Durning
cell: 508-561-9963